Derrick



(No Model.)

J. B. HARRISON. DERRICK.

No. 412,087,. PatentedOct. 1, 1889.

UNITED STATES JAMES BENJAMIN HARRISON, OF SAN JOSE, CALIFORNIA.

DERRICK.

SPECIFICATION forming part Of Letters Patent NO. 412,087, dated. October 1, 1889.

Application filed I 1111a 14, 1389. Serial No 314,296- (No model.)

V To all whom it may concern.-

Be it known that 1, JAMES BENJAMIN HAR- RIsON, of San Jose, Santa Clara county, State of California, have invented an Improvement in Derricks; and I hereby declare the following to be a full, clear, and exact description of the same.

My invent-ion relates to the class of derricks 5 and my invention consists in the hereinafterdescribed novel construction and arrangements of parts, the object of which is to en able the load to be raised and simultaneously turned to a varying position of discharge, according as may be desired.

Referring to the accompanying drawing for a more complete explanation of my invention, the figure is a perspective view of my derrick.

A is the foundation plate or timbers of the derrick, in the center of which is stepped at a the mast B, which is adapted to have an axially-rotary motion, said mast being supported and guided in a suitable box 0, carried by the braces c. The top of the mast has secured to it a cross beam or boom D, which is stiffened by braces d. In one end of the cross beam or boom is a sheave E and in the other end a sheave F. Secured to the box C is a swinging or swiveled guide-sheave G, and on the base-timbers A is a directing-sheave H.

I is the hoisting rope or cable, one end of which is adapted to be attached to the load. It thence passes upwardly over the sheave E, and along the top of the cross-beam and down over the sheave F, thence downwardly over the swinging guide-sheave G, and thence under the directing sheave H.

Secured to the mast near its base isa pulley J, to which the rope or cable K is attached, and passes thence between directing-sheaves L, as shown.

M designates any suitable source of power, horse or engine, and it will be seen that both cords or cables I and K are attached directly to this same source of power, so that both are operated simultaneously.

N is a spring acting on the axially-rotary mast and adapted to return it to its primary or initial position.

O is a limiting rope or cable attached to the base of the mast to prevent the spring from turning it beyond its primary or initial position. The face of the pulley J is provided with teeth 3', forming it into a ratchetsurface. With this ratchet is adapted to engage a swinging retainingpawl P, controlled by a spring 19, and carried by a bracket 19' on the base-timbers.

Q is a latch engaging the pawl for holding it back out of engagement when not in use.

The derrick when set up ready for use is steadied by means of ballast orweights upon its base frame or timbers, and, if desired, suit able guys may be used to further steady it.

Its operation is as follows: Both ropes or cables I and K, being attached to the same source of power, are operated simultaneously, so that as the hoisting rope or cable I is drawn in the load is raised, and at the same time the turning rope or cable K, being drawn in, turns the mast axially, so as to carry the load to the position for discharging or unloading it. As soon as the load is discharged and the ropes or cables slackened up, the spring N returns the derrick to its primary or initial position, this position being defined by the limitin -rope 0. If it be desired to hold the derrick in any particular position to which it may be turned, the retaining-pawl I? is relieved of its latch Q, so that it springs to its engagementwith the ratchet face j of the pulley J, and when the strain of the ropes or cables is relieved the derrick will stay in the position to which it has been turned, being held there by the pawl.-

If it be desired to raise the load a short distance before turning the derrick, all that is necessary is to slack up on the turning-rope K, so that said rope will not be made taut until the hoisting-rope has been drawn in a sufficient distance, when both ropes will be drawn in together.

It will be seen that by reason of the crossbeam or boom D on top of the mast B, the arrangement of the sheaves E and F in the ends thereof, and the passage of the hoistingrope I over them, as described, a balance is given to the machine, the strain on the hoisting-rope at one end of the beam or boom bal ancing the strain of the load on the other end, so that the entire device operates and moves easily.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is

1. In a derrick, the combination of the axially-rotary mast, the cross-beam on its top,

the sheave in each end of said beam, the hoisting-rope passing from the load end over said sheaves to the power, a pulley on said mast, having ratchet-teeth, a pawl for engaging said teeth, a'turning-rope secured to said pul- I ley, whereby the mast may be turned, and a spring for returning the mast, substantially as described. I

2. In a derrick, the combination of the ax- I ially-rotary mast, the crossbeam on its top, the sheave in each end thereof, a swiveled sheave on the mast, the hoisting-rope passing from the load end over said sheaves to the power, the pulley J on the mast, the turningrope secured to said pulley, whereby the mast is'turned, a retaining=pawl for the puli ley, a latch for said pawl, a spring for return- 1' ing the mast, and a source of power common to both ropes, whereby the load is raised and directed simultaneously, substantially as described.

3. In a derrick, the combination of an axially-rotary mast, the cross-beam on its top, the sheave in each end thereof, the hoisting rope passing over said sheaves, guide-sheaves for said rope, the pulley J on the mast, having the ratchet-face, the turning-rope secured to said pulley, and a retaining-pawl engaging the ratchet-faced pulley, substantially as described.

In witness whereof I have hereunto set my hand.

JAMES BENJAMIN HARRISON. Witnesses:

J. E. FISHER, H. J ALEXANDER. 

